LAD #36: Truman Doctrine

The Truman Doctrine effectively began the Cold War.  The Soviet Union was expanding into what was known as the Soviet Sphere, or the small countries around the Soviet Union which were under the nation's control.  In an effort to combat this, President Truman issued the Truman Doctrine, which pledged economic and military aid to Greece and Turkey so that they would not fall to Communism.
The Truman Doctrine evolved to form the basis of the United States' foreign policy during the Cold War.  Truman believed in protecting all nations who resisted the influence of Communism.  This foreign policy was known as Containment because the primary goal of America was to contain the spread of Communism and restrict the Soviet Union's power as much as possible.